Circuit breaker control system



May 11, 1948. A. HALLER CIRCUIT BREAKER CONTROL SYSTEMS Filed Sept. 11, 1944 Patented May 11,1948

CIRCUIT BREAKER CONTROL SYSTEM Arnold Haller, Baden, Switzerland, assignor to Aktiengesellschaft Brown, 'Boveri & Cie., Baden,

- Switzerland Application September 11, 1944, Serial No. 553,632 In Switzerland September 11, 1943 14 Claims. 1

The control system of a pneumatically operated circuit breaker has to transmit switching orders of all kinds to the actuating elements of the moveable switch contacts. The switching movements must always be clear and complete, quite independently of the fact whether the orders are short or long, contradict each other, occur in rapid succession, or are merely a repetition of some orders which have already been exeouted.

The object of the present invention is to provide a control system for a pneumatically operated electric circuit breaker where all the aforementioned conditions can be readily fulfilled. According to the invention this'is achieved due to the control valves both for the closing and opening order being actuated by power storage devices whose charging organs are controlled by the moveable contact of the circuit breaker.

A constructional example of the invention is illustrated diagrammatically in the accompanying drawing where Fig. 1 shows a circuit breaker, the pneumatic drive and control being shown in longitudinal section. Fig. 2 shows the control system during the opening or. circuit-breaking process.

The essential elements required for the control and switching operations of the circuit breaker are shown in Fig. l. The moveable switch blade i of the circuit breaker is controlled in its end position in and out by supplying compressed air to one or the other side of the piston 2. For this purpose compressed air is supplied from container 3 over valve 4 or! and pipe 5 or '5 respectively to the working cylinder 6. Valves 4, 4' which are moved by levers '1, 1 respectively are actuated by power storage devices which in this case consist of toggle levers 8, 8' and springs 9, 9. In Fig. 1 the circuit breaker is shown in the closed position. The left-hand power storage device which serves to open the circuit breaker is thus held by catch H) in the extended position, whilst the right hand power storage device for the closing orders is kept extended by its holding catch Ill and furthermore by the charging cam II. The left-hand storage device is also provided with a corresponding charging cam ,ll, both cams H, II being actuated from the switch blade I by way of shaft 12 and link I 3. Holding catches III, III engage release catches l4 and I4 respectively, and Fig. 1 shows how commanding impulses are transmitted by various command elements so as to cause a vertical movement of these release catches I4, l4. The commanding elements consist for instance of press-buttons l5 and i5 which are at the same time constructed as the cores of remote-controlled magnets l6 and iii, a second remote-controlled magnet l1 serving for switching-out purposes and a lowvoltage magnet it which causes an interruption when the coil is not excited, also being provldeda block is provided in the form of an over-current relay l9 which also actuates the release catch it by means of a link 20.

In order to be able to block operation of the circuit breaker under certain circumstances which are referred to in greater detail later on, a rod 2i is provided which is actuated by lever 1 or I and causes the release catches Hand [4' respectively to disengage the holding catches I0, 10'. Blocking rod 2i is also actuated by a pressure measuring device 22, which when the pressure in ccntainer 3 drops below a certain minimum value operates and also blocks the control.

The method of operation of the control arrangement is as follows:

Commencing with the circuit breaker in the position shown in Fig. 1, when a switching-out order is transmitted by one of the commanding elements l5, It, H or ill, the left-hand power storage device 8, 9 is released due to the vertical movement of the release catch l4 and the rocking 0f the holding catch iii; toggle lever B bends upwards and spring 9 opens valve 4 by means of lever i. This action is illustratedin Fig. 2. At the same time lever I has moved rod 2! to the left so thatrelease catches i4, M are disengaged from the holding catches Ill, [0 of both power'storage devices. It is thus clear that once the switohing out operation has been initiated it cannot be influenced by external means, that is neither by prematurely interrupting the switching order nor by a counter-order to switch in with catch l4. Release catches l4, it only come into engagement again with holding catches 80, Hi when upon completion of the switchingout order, circuit breaker switch blade I by means of link 13 and shaft l2 has rotated charging cam I I, whereupon the left-hand power storage device 8, 9 becomes recharged and valve 4 closed. At the same time charging cam II' which is mounted on shaft [2 is also rotated so that the right-hand power storage device is ready to execute a switching-out order.

The switching-in operation which can be initiated by the commanding elements I5 or IE only after the breaker has moved to full open position, the valve 4 has reclosed, and release catch l4 returned to engagement with its associated holding catch It by movement in the opposite direction of rod 2|, is performed in a similar manner to the switching-out operation just described and does not require any further explanation. It only requires to be emphasized that also a switching-in operation, once it has commenced, cannot be influenced by any further switching orders until the circuit breaker has fully completed its closing operation.

I claim:

1. In a circuit interrupter, the combination with a movable switch blade, a power cylinder and piston for moving said switch blade into and out of engagement with a cooperating switch element, a source of pressure gas, and independently operable valves for controlling communication between said pressure gas source and the respective ends of said power cylinder; of means including individual power devices for opening the respective valves, means mechanically connected to and operable with said switch blade for storing power in said power devices, and means selectively operable to release one or the other of said power devices for movement to open the associated valve, thereby to admit pressure gas to an end of said power cylinder for a movement of the switch blade in one direction.

2., In a circuit interrupter, the invention as recited in claim 1, in combination with means mechanically connecting said power devices and operated by the initial release movement of one power device to prevent a release of the second power device prior to the completion of the switch blade movement resulting from said release of the first power device.

3. In a circuit interrupter, the invention as recited in claim 1 wherein said means for storing power in said power devices comprises means operable near the end of the movement of the switch blade in either direction by said piston to store power in the power device that was released to open the valve that initiated the piston movement.

4. In a circuit interrupter, the invention as recited in claim 1 wherein said means for storing power in said power devices includes means operable when said switch blade is in either end position to prevent a release of the power device of the control valve that was last opened to effect movement of the switch blade into that end position.

5. In a circuit interrupter, the invention as recited in claim 1 wherein said power devices are spring-loaded toggle levers.

6. In a circuit interrupter, the invention as recited in claim 1, in combination with means responsive to decreased pressure of said pressure gas source to prevent release of said power devices.

7. In a circuit interrupter, the combination with a jaw contact, a switch blade, a power power device.

cylinder and piston for moving said switch blade into and out of engagement with said jaw contact, a source of pressure gas, passage means including valves for connecting said pressure gas source selectively to the respective ends of said power cylinder to effect movement of said switch blade in opposite directions, of means for controlling the operation of said valves; said valve controlling means comprising spring means for actuating the respective valves, means actuated by movement of the switch blade in one direction to stress the spring means of the valve that was opened to effect movement of the switch blade in that direction, means automatically latching the stressed spring means to prevent its operation of the associated valve, and means for unlatching said stressed spring means of the pair of valves.

8. In a circuit interrupter, the invention as recited in claim '7 wherein said unlatching means is manually actuated.

9. In a circuit interrupter, the invention as recited in claim '7 wherein said unlatching means is actuated by relay means responsive to the current through the circuit interrupter.

10. In a circuit interrupter, the invention as recited in claim 7 wherein said unlatching means is controlled by the pressure of the gas within said pressure gas source.

ll. In a circuit interrupter, the invention as recited in claim 7, wherein said means for stressing a spring means blocks actuation of the associated valve by that spring means prior to an opening of the other valve by an unlatching of its spring means.

12. In a circuit interrupter, the invention as recited in claim '7 wherein said spring means comprise spring loaded toggle mechanisms.

13. In a circuit interrupter, the invention as recited in claim '7 wherein said spring means comprise spring loaded toggle mechanisms; and said latching means comprises a holding catch for retaining the associated toggle mechanism in spring-stressed condition.

14. In a circuit breaker including a power cylinder and a piston for actuating a movable contact into and out of engagement with a stationary contact, a source of pressure gas, valves controlling the flow of pressure gas to the opposite ends of said cylinder, power devices for opening the respective valves, means actuated in response to operation of the circuit breaker con tacts for storing power in said power devices, means selectively operable to release each of said power devices to open or close said contacts, and interlock means actuated upon release of one of said power devices to prevent release of the second power device prior to completion of the opening or closing operation of the circuit breaker contacts resulting from the release of said first ARNOLD HALLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

